The invention relates generally to a friction brake for a motor vehicle.
From German Patent Disclosure DE 42 07 640 A1, a friction brake embodied as a disk brake is known. The known friction brake has a brake disk as its brake body, against which a friction brake lining can be pressed to generate a braking moment or braking force. For pressing the friction brake lining against the brake body, the known friction brake has a piston, which is displaceable perpendicular to the brake disk by means of a wedge drive mechanism, by rotation about a piston axis, and which presses the friction brake lining against the brake disk.
A driving energy for rotating and displacing the brake piston is drawn from the rotatable brake body by a controllable, electromagnetic friction coupling. The friction coupling is embodied annularly and is disposed coaxially to a rotary axis of the brake body. A circular-disk-shaped coupling lining is mounted fixedly and coaxially to the brake body and rotates along with the brake body. An electromagnetic part, having a winding, of the friction coupling is embodied annularly and is disposed rotatably and coaxially to the brake body. Supplying electric current to the winding causes the electromagnetic part of the friction coupling to achieve frictional engagement with a coupling lining that is solidly attached to the brake body and rotates along with it, so that the electromagnetic part of the friction coupling is driven to a rotary motion by the brake body. A driving moment exerted on the electromagnetic part of the friction coupling by the brake body is dependent on an intensity of the current with which the winding of the electromagnetic friction coupling is supplied. The electromagnetic part of the friction coupling has a set of teeth, which meshes with a set of teeth of the piston of the actuating device, so that supplying current to the winding of the friction coupling drives the piston to rotate, thus pressing the friction brake lining against the brake body.